Erosion of the refractory lining is a significant cost factor in the operation of metallurgical furnaces. There are several mechanisms by which the refractory can be eroded, such as by simple melting, chemical dissolution by hot melts or slags, spalling due to thermal cycling and mechanical erosion by impaction of liquid or solid particles. These mechanisms may operate singly or in combination with one another and often erosion will occur in localized regions of the furnace. Regardless of the form the erosion takes, its severity accelerates in direct proportion to the temperature to which the refractory material is subjected.
Where erosion is severe it is necessary to terminate operation of the furnace in order to repair or replace the affected material. In some instances lining life can be extended by temporary hot patching; however, it has been proposed to reduce the severity of erosion by providing means for water cooling the refractory lining or the furnace wall to which it is applied. These cooling means serve to remove the heat input to the lining thereby to cool the adjacent refractory material. Examples of such water cooling apparatus are disclosed in U.S. Pat. Nos. 3,593,975, 3,598,382, 3,679,194 and 3,777,043.
Although the cited water cooling apparatus is effective to extend refractory lining life, their effectiveness is influenced negatively by the fact that they commonly operate at such coolant flow velocities that steaming is apt to occur. When steaming occurs the hot surface of the water jacket is prone to have formed thereon a steam blanket which is a thin layer of vapor. This layer of vapor acts as a thermal insulator thereby retarding the transfer of heat from the refractory lining into the coolant fluid and concomitantly reducing the effect of the fluid cooling.
It is to the improvement of such apparatus therefore that the present invention is directed.